Not Applicable.
Not Applicable.
The present invention relates to wheelchairs for use by disabled persons. More specifically, the present invention relates to a detachable foot support assembly that has adjustable wheels to allow it to function as an anti-tip device or to assist the wheelchair in overcoming obstacles.
A common problem associated with three-quarter drive or mid-wheel drive wheelchairs is the tendency to tip or become unstable when the wheelchair is either stopping or moving down an incline. When the unit tips, the user could fall out of the wheelchair if not supported by a seat belt, or the whole unit could tip over. This problem is typically addressed by providing a set of anti-tip wheels on either the front of the wheelchair to prevent tipping forward or on the back of the wheelchair to prevent tipping backward. These anti-tip wheels are usually located in close proximity to the ground to allow for greater stability and less space for the chair to tip.
Another common problem for wheelchair users is the difficulty of maneuvering the wheelchair over objects such as curbs or other physical barriers. When faced with a barrier that is not convenient or possible to circumnavigate, the wheelchair user can attempt to go over the barrier. However, this can result in damage to the wheelchair. For example, the front of the chair can be damaged or, if the front of the unit successfully climbs the barrier, the chair may become stuck or grounded on the barrier if the rear wheels are not able to overcome the barrier. Thus, the user is not only stranded but the wheelchair undercarriage and frame might also suffer damage.
One way to address this problem is to provide a set of wheels on the front end of the wheelchair assembly in a manner that allows the wheels to engage the barrier and assist the wheelchair in rolling over the barrier by raising the entire assembly. To perform this function, such wheels may be disposed higher above the ground than typical anti-tip wheels and are preferably adjusted to the approximate height of the typical barrier that is encountered.
This type of assembly has inherent disadvantages. For example, another deficiency of the known configurations is that in order to convert the wheels from anti-tip to barrier hurdle mode, the wheelchair must be disassembled and tools are required to make the required adjustments. Not only is this time consuming and inconvenient, but many wheelchair users cannot perform the transformation without assistance.
An attempted resolution of these problems is to provide a wheel assembly wherein the wheels are adjustable by virtue of being mounted with a resilient suspensionxe2x80x94typically with springs. In this prior art solution, the anti-tip wheels are set in a position relatively low to the ground. This allows the wheels to serve an anti-tip function. When the wheels encounter a barrier, the springs are designed to xe2x80x9cgive,xe2x80x9d allowing the anti-tip wheels to be raised. This attempted resolution is deficient in that the spring tension in the suspension is difficult to set correctly for both situations. If not enough tension is present, the anti-tip wheels will not prevent the wheelchair from tipping, or at least severely rocking forward. If too much tension is present, the springs will not allow the wheels to raise up upon encountering a barrier, which could damage the wheelchair.
Although it is apparent that wheelchairs equipped with the resilient suspension can be set to address one of the two above-mentioned problems at any given time, it is difficult to achieve a setting that addresses both of the above-mentioned situations.
An anti-tip assembly for a wheelchair is therefore needed which will provide enough flexibility to give the chair the required range of motion to overcome obstacles and to provide anti-tip features, while at the same time being convenient and easy to adjust.
It is an object of the present invention to provide an anti-tip assembly for wheelchairs for use by disabled persons that can easily be converted from an anti-tip position to a barrier hurdle position.
It is another object of the present invention to provide an anti-tip assembly for wheelchairs that can be transformed from an anti-tip position to a barrier hurdle position without tools and by hand pressure alone.
A still further object of the present invention is to provide an anti-tip assembly for wheelchairs that can be adjusted with relative speed and ease.
According to the present invention, the foregoing and other objects are obtained by an anti-tip assembly for wheelchairs. The anti-tip assembly has a support frame being adapted to be coupled to the wheelchair. A first and a second wheel support arm extend outwardly from the support frame and are pivotally coupled thereto. A wheel is rotatably connected to each of the support arms. An adjusting mechanism is coupled between the frame and the support arms. The adjusting mechanism is adapted to change the position of the support arms relative to the frame. In this manner, the adjusting mechanism is adapted to raise and lower the wheels. The anti-tip wheels of the wheelchair are thus adjustable to different fixed positions relative to the support frame by operation of the adjusting mechanism.
Additional objects, advantages, and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.